The present invention relates to a method of, and system for, editing video information including video image frame data and audio sample data, and particularly to the techniques for editing images and sounds such as television broadcast programs, video image works, animation products, recorded images of TV phone or video data produced by computer in order to be reproducible at different speeds from the standard record/reproduce speed.
In the conventional TV program production, a plurality of video tape recorders and video monitors are used, and the video image data and audio data recorded in the original tapes are edited by repeating the first forward or rewinding operations while watching the tape counters and monitor screens. In recent years, a computer has been introduced in the television broadcast program production facilities and video soft production equipment, making it possible to edit highly efficiently and functionally.
According to the video information editing using a computer, the video image data and audio data are converted into digital signals and recorded in a memory unit such as a magnetic hard disk unit.
The video information editing system using a hard disk unit, when operated to edit moving pictures of images and sounds, generally produces, as for example shown in FIG. 8, an operation panel, a control window 800 and a moving picture 802 being edited on a display monitor connected to a system control computer which constitutes the video information editing system, according to editing software.
The user operates the mouse connected to the system control computer to put the cursor on a slider 801, a push button 803 and so on displayed on the operation panel and control window 800, and then, for example, clicks or drugs the cursor on the display monitor, thereby editing the video data.
The video information editing system has a reproduce function (preview) provided to confirm the recorded contents of the hard disk unit and the edited picture and sound. That is, at the time of editing, an image is displayed on the monitor and sound is produced from the speaker connected to the system control computer on the basis of the video image data and audio data recorded on the hard disk unit and under the software control as described above, thus those contents being confirmed.
In this video information editing system, the video image data and audio data recorded on the hard disk unit are reproduced at the standard speed by successively producing the video image signal and audio signal to the display monitor and speaker in the order of frames while the video image data and audio data are synchronized at each frame which constitutes a moving picture.
In the conventional video information editing operation using tape recorders, the video information can be easily reproduced at a different speed from the standard speed, for example, in the slow speed mode or fast speed mode by changing the tape transport speed (change of frame rate). However, the video information data recorded in a form of digital data on the hard disk unit cannot be reproduced in the slow speed mode or fast speed mode by changing the rotation speed of the hard disk unit, because the hard disk unit must always be operated at a constant revolution speed.
Here, we will define the term xe2x80x9creproduction speedxe2x80x9d used in this specification as below. The reproduction at the standard speed is that the frame images picked-up or recorded at a predetermined frame rate are reproduced at the same frame rate. When the frame images photographed at a rate of, for example, 30 frames per second are reproduced at the same frame rate of 30 frames per second, the reproduced images move at the same content speed (speed of contents) as the original images, or at the standard speed. The slow speed reproduction mode is the way to reproduce so that the reproduced images can move more slowly than those reproduced at the standard speed. The fast speed reproduction mode is the way to reproduce so that the reproduced images can move more faster than those reproduced at the standard speed.
It is an object of the present invention to provide a method and system for editing so that the video information recorded in a digital form in a hard disk unit or the like can be reproduced at a different speed from the standard reproduction speed, and a recording medium with the editing method program recorded.
According to the present invention, there is provided a method of editing digital video information including a plurality of frame image data and audio sample data associated with each frame image data. In the editing method and editing system of the present invention, when a mode of reproduction speed for video images is specified, a frame reading pattern described later is selected from the reproduction patterns (frame reading patterns) stored in a memory, frame image data is read out of a video image data source according to the selected frame reading pattern, audio sample data is read out of an audio data source according to the frame reading pattern, the read frame image data is produced at a predetermined frame rate, and the read audio data is produced in synchronism with the produced frame image data.
In addition, there is provided a recording medium in which a program for the editing method is previously recorded in a form of program code which can be read by a computer. This recording medium is, for example, a magnetic disk, an optical disk or a semiconductor memory.
According to the video information editing method of the present invention, the audio data is read from the audio data source in accordance with the predetermined frame reading pattern, the data is processed and outputted in synchronism with the frame image when the video data is reproduced at a different speed from the standard reproduction speed. Accordingly, the editor can listen the reproduced sound with shifted audio frequency band in non-standard speed reproduction mode (a slow or fast speed mode). That is, the frequency of reproduced sound in a slow speed mode has been shifted to lower frequency band than the sound frequency band of standard speed mode. Meanwhile the frequency of reproduced sound in a fast speed mode has been shifted to higher frequency band than the sound frequency band of standard speed mode. The shift of the frequency band depends on the speed ratio between the speeds of non-standard mode and standard mode. Such sound reproduction in the non-standard mode of the present invention gives to the editor or user a feeling similar to the sound reproduction in non-standard speed mode of the video tape recorder. The user can edit the digital video data from the hard disks in the feeling same as that of editing work with the video tape recorder. Unnecessary distortion in the reproduced sound of non-standard mode can be reduced. The viewer, who watches the pictures from the edited video data, can listen smooth sound corresponding to the reproduced images in non-standard speed mode.